Hi Christine.  Here is what I did because we haven't the $ to buy fancy roof
racks and I wanted to use our old ten dollar racks we bought from Sally Ann.

Made up four  four inch long brackets shaped like a <J>, out of 3/16
aluminum plate.  At the rear I used one of the bolts that holds the top onto
the hinge.  Then I drilled through the bracket top and hinge and put in a
second bolt.  Thus the weight on the rack is transferred to the steel hinge
plate and directly onto the roof.  No stress on the pop top.

At the front, I mounted the brackets on the luggage rack over the cab.  I
took this off for other reasons and installed the brackets then.  For this
one, I used a second sheet of plate inside the cap so the fibreglass became
the meat in the sandwich so to speak.

The system has worked well.  Our kayak weighs 130 lbs. and we have had no
problems.  I have also carried lumber but not too much.  Don't want to
become top heavy.

Also, I keep the rear mattress in the basement unless we are taking a trip.
Have an old piece of carpet over the engine lid and "stuf" goes back there
where it won't slide around too much.  If I have a long load, fold the back
seat down and put a piece of cardboard over the seat cushions.  Have carried
a couple of sheets of plywood that way for short trips.]

Earl from Sunny Sooke, B.C.
 At the tip of soon-to-be-overloaded-and-sink Vancouver Island
84 ex-California Westie